PRODUCING BIOCHAR BY SEVERE TORREFACTION OF OAK, TO SUBSTITUTE FOSSIL COAL IN METALLURGY INDUSTRY. LABORATORY AND PILOT SCALE INVESTIGATIONS

In the overall efforts to reduce fossil CO2 emissions, in which EU has taken engagements, industry will have a prominent contribution. In this context, the CIRMET European project aims at evaluating the use of torrefied biomass as heating source and reducing agent in metallurgy furnaces. So far, coal or coke are used for that purpose.
Torrefaction is a thermal process which changes biomass into a solid with properties closer to coal. Therefore, producing a substitute for coal by torrefaction of biomass could be a relevant option. To be used as reducing agent in metallurgy processes requires the biochar to have a fixed carbon content above 85% and to contain as few inorganics as possible [1] . Such requirements can preferably be met after torrefaction of wood operated under severe conditions.
This work is focused on the preparation of a high carbon content biochar, by torrefaction of oak wood chips at 300 and 350°C. This treatment is performed in a pilot scale furnace. Prior to those large scale operations, some experimental investigations have been carried out with TGA to identify optimal conditions for the thermal treatment.